Can’t set WA_TranslucentBackground to a QWidget

    #include <QtWidgets/QApplication>
    #include <QLabel>
     
    int main(int argc, char *argv[])
    {
     QScopedPointer<QApplication> app(new QApplication(argc, argv));
     
     QWidget w;
     w.resize(500, 400);
     QPalette palette = w.palette();
     palette.setColor(QPalette::Base, Qt::transparent);
     w.setPalette(palette);
     w.setAttribute(Qt::WA_TranslucentBackground);  //this line will make the program crash
     w.setWindowFlags(Qt::FramelessWindowHint);
     
     QLabel *label = new QLabel("Some label", &w);
            label->setObjectName("label");
     
     w.show();
     
     return app->exec();
    }